In Colorado when you get a license you’re registered as undecided. You can opt to register as any party, but if you remain undecided then each primary election you get mailed a Republican and Democrat ballot. You’re automatically mailed ballots for standard elections, and an info packet covering any question you might have about ballot measures.

You can take that ballot and mail it in, leave it in a drop box, or hand it to a drive through elections officer/collector without leaving your car. You can also just vote in person. All that for early voting period through to election day.